SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8cafe6ab3d6ca4fbf6f146f2a3e164cf7b3d60cca31341eb608becb85ad3dc49' 
  AND token = 'mWOuDqXfORiFVAjUPTqG80hDBYuwxUJfFKK7E3wCcRc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}